CBSE Class 12 Chemistry Revision (1). CBSE issues sample papers every year for students for class 12 board exams. Students should solve the CBSE issued sample papers to understand the pattern of the question paper which will come in class 12 board exams this year. The sample papers have been provided with marking scheme. It’s always recommended to practice as many CBSE sample papers as possible before the board examinations. Sample papers should be always practiced in examination condition at home or school and the student should show the answers to teachers for checking or compare with the answers provided. Students can download the sample papers in pdf format free and score better marks in examinations. Refer to other links too for latest sample papers.
1.‘Stability of a crystal is reflected in the magnitude of its melting point’. Comment.
2.Why does LiCl acquire pink colour when heated in Li vapour?
3.Explain the following terms with a suitable example:
a) 12 – 16 compounds
4.Write equation for the following:
a) Finkelstein reaction
b) Sandmeyer reaction
5.A unit cell consists of a cube in which there are A atoms at the corners and B atoms at the face centres. Two A atoms are missing from the two corners of the unit cell. What is the formula of the compound?
6.An optically active halide of formula C4H9Br undergoes substitution by OH─ with an inversion of configuration. Explain the mechanism involved in the reaction.
7.a) Distinguish between the following pairs:
1- Chlorobutane and 1- Chlorobutene
b) Predict the order of reactivity of the following compounds in SN1 reactions:
C6H5CH2Br, C6H5CH(C6H5)Br, C6H5CH(CH3)Br, C6H5C(CH3)(C6H5)Br
c) Write the IUPAC name of the following:
8.An element occurs in bcc structure. It has a cell edge length of 250 pm. Calculate the molar mass if its density is 8.0 g cm-3.
9.How will you bring about the following conversions:
a) Propene to 1- Nitropropane
b) Benzyl alcohol to Benzyl cyanide
c) Chlorobenzene to p- nitrophenol
10.a) If KCl is doped with 10-4 mole % of CdCl2, what is the concentration of cation vacancy? b) A compound forms a hexagonal closed packed structure. What is the total number of voids in 0.5 mol of it?
11.a) What are enantiomers? b) Explain why?
i) Grignard reagent should be prepared under anhydrous conditions.
ii) Tertiary halides do not undergo SN2 mechanism.
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